A stand arrangement of this kind is known from U.S. Pat. No. 5,528,417. There, a stand arrangement for a medical-optical instrument is described which carries medical-optical equipment on a holding unit via first and second parallel linkage pairs. The medical-optical equipment is accommodated on a front link of a parallel linkage pair which is connected via a third linkage unit to a rotatably journalled device for force transmission in the form of a crank member. This crank member is coupled to the holding unit via a further rigid link unit. The crank member causes the front link to assume a specific orientation independently of the position of the first and second parallel linkage pairs in each position of the medical-optical equipment.
In U.S. patent application publication 2004/0190131 A1, a stand arrangement for a medical-optical instrument of the above-mentioned kind is described wherein a toothed gearing is provided for coupling the holding unit and the linkage-shaped configured means for force transmission.